IL17A, also known as Interleukin 17, is a cytokine that acts as a potent mediator in delayed-type reactions by increasing chemokine production in various tissues to recruit monocytes and neutrophils to the site of inflammation. It is produced by T-helper cells and is induced by IL23 which results in destructive tissue damage in delayed-type reactions. This protein is a 155 amino acid protein that is a disulfide-linked, homodimeric, secreted glycoprotein with a molecular mass of 35kDa. The structure of IL17A consists of a signal peptide of 23 amino acids followed by a 123 aa chain region characteristic of the IL17 family. An N-linked glycosylation site on the protein was first identified after purification of the protein revealed two bands, one at 15kDa and another at 20kDa. Recombinant human IL17A, fused to His-tag at C-terminus, was expressed in insect cell and purified by using conventional chromatography techniques.